template

The template package provides a lightweight string template engine. Templates use {{key}} placeholders that are replaced with values from a hashmap.

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Package Functions

render(tmpl, vars)

Renders a template string, replacing every {{key}} occurrence with the corresponding value from vars.

Parameters

Type	Name	Description
string	tmpl	Template string with {{key}} placeholders
hashmap	vars	Map of variable names to replacement values

Returns

Type	Description
string	The rendered string

Values are converted to strings via .to_string() automatically.

---

render_file(path, vars)

Reads a template from a file and renders it with the given variables.

Parameters

Type	Name	Description
string	path	Path to the template file
hashmap	vars	Map of variable names to values

Returns

Type	Description
string	The rendered string

---

render_each(tmpl, rows)

Renders a template once per row in a list, returning a list of rendered strings.

Parameters

Type	Name	Description
string	tmpl	Template string with {{key}} placeholders
list	rows	List of hashmaps — one hashmap per output line

Returns

Type	Description
list	List of rendered strings, one per row

---

Examples

Basic substitution

import "template"

result = template::render("Hello, {{name}}! You are {{age}} years old.", {
  "name": "Alice",
  "age": 30
})

println result   # Hello, Alice! You are 30 years old.

HTML template

import "template"

html = template::render("<h1>{{title}}</h1><p>{{body}}</p>", {
  "title": "Welcome",
  "body":  "Thanks for visiting."
})

println html

Render from file

Given email.txt:

Subject: {{subject}}

Hello {{name}},

{{message}}

Regards,
{{sender}}

import "template"

text = template::render_file("email.txt", {
  "subject": "Your order shipped",
  "name":    "Bob",
  "message": "Your order #4521 is on its way.",
  "sender":  "Support Team"
})

println text

Batch rendering

import "template"

rows = template::render_each("{{id}}: {{name}} <{{email}}>", [
  { "id": 1, "name": "Alice", "email": "alice@example.com" },
  { "id": 2, "name": "Bob",   "email": "bob@example.com"   },
  { "id": 3, "name": "Carol", "email": "carol@example.com" }
])

println rows.join("\n")
# 1: Alice <alice@example.com>
# 2: Bob <bob@example.com>
# 3: Carol <carol@example.com>

Combining with fio for report generation

import "template"
import "fio"

data = fio::read_text("report_template.html")
output = template::render(data, {
  "title":   "Monthly Summary",
  "month":   "March",
  "revenue": "42,000"
})

fio::write_text("report_march.html", output)